1. Field of the Invention
The present invention relates to a tire pressure cover utilizing colors to indicate tire pressure.
2. Description of the Prior Art
In the past, to judge the size of tire pressure, users generally use the hand to press the tire and "feel" whether the pressure is adequate, which is not scientific. Besides, the possibility of error is high. There have been developed different kinds of meters or gauges to facilitate the measurement of tire pressure. However, such meters or gauges can be used to measure the tire pressure at a given time. There is no device available to track the tire pressure over a period of time or warn the user when the tire pressure is insufficient.
A prior art device discloses an air nozzle accommodating therein an inner air chamber and an outer air chamber in a two-layer construction. A narrow channel connects the inner and outer air chambers, and a buoy is disposed in the channel and is caused to move upwardly or downwardly by the pressure between the air chambers so as to indicate the size of pressure inside the tire. However, there is not any markings on the buoy to indicate the size of the tire pressure, and the judgment of tire pressure depends mainly on the movement of the buoy. Precision is therefore very low. In addition, such prior art devices are complicated in construction and hence costly to manufacture.